A physical impact to the head of a person may cause serious injury or death. To reduce the probability of such consequences, head protection gear, such as a helmet, is often used in activities that are associated with an increased level of risk for a head injury. Examples of such activities include, but are not limited to, bicycling, rollerblading, rock climbing, skate boarding, skiing, and motorcycling.
The ability of a helmet to protect the head depends at least in part on the proper fitting of the helmet on a person's head. To accommodate different head sizes and head shapes of the general population, a helmet typically has a fitting mechanism, which includes adjustable straps that hold the helmet on the user's head and a belt that conforms to the circumference of the user's head. The effectiveness of the fitting mechanism to achieve a proper fit on a user's head, as well as the associated level of convenience and comfort, affect the helmet's ability to provide head protection to a user.